add allow_head to add_get, fix #1618

aiohttp/abc.py

@@ -14,10 +14,9 @@ def __init__(self):
     def post_init(self, app):
         """Post init stage.
 
-        It's not an abstract method for sake of backward compatibility
-        but if router wans to be aware about application it should
-        override it.
-
+        Not an abstract method for sake of backward compatibility,
+        but if the router wants to be aware of the application
+        it can override this.
         """
 
     @property

aiohttp/web_urldispatcher.py

@@ -715,6 +715,7 @@ def __init__(self):
         super().__init__()
         self._resources = []
         self._named_resources = {}
+        self._default_allow_head = False
 
     @asyncio.coroutine
     def resolve(self, request):
@@ -755,6 +756,9 @@ def routes(self):
     def named_resources(self):
         return MappingProxyType(self._named_resources)
 
+    def set_defaults(self, *, allow_head):
+        self._default_allow_head = allow_head
+
     def register_resource(self, resource):
         assert isinstance(resource, AbstractResource), \
             'Instance of AbstractResource class is required, got {!r}'.format(
@@ -855,11 +859,16 @@ def add_head(self, *args, **kwargs):
         """
         return self.add_route(hdrs.METH_HEAD, *args, **kwargs)
 
-    def add_get(self, *args, **kwargs):
+    def add_get(self, *args, allow_head=None, name=None, **kwargs):
         """
-        Shortcut for add_route with method GET
+        Shortcut for add_route with method GET, if allow_head is true another
+        route is added allowing head requests to the same endpoint
         """
-        return self.add_route(hdrs.METH_GET, *args, **kwargs)
+        if allow_head or (allow_head is None and self._default_allow_head):
+            # the head route can't have "name" set or it would conflict with
+            # the GET route below
+            self.add_route(hdrs.METH_HEAD, *args, **kwargs)
+        return self.add_route(hdrs.METH_GET, *args, name=name, **kwargs)
 
     def add_post(self, *args, **kwargs):
         """

tests/test_web_urldispatcher.py

@@ -310,3 +310,63 @@ def resolve(self, request):
     resp = yield from client.get('/')
 
     assert resp.status == 412
+
+
+@asyncio.coroutine
+def test_allow_head(loop, test_client):
+    """
+    Test allow_head on routes.
+    """
+    app = web.Application(loop=loop)
+
+    def handler(_):
+        return web.Response()
+    app.router.add_get('/a', handler, allow_head=True, name='a')
+    app.router.add_get('/b', handler, allow_head=False, name='b')
+    client = yield from test_client(app)
+
+    r = yield from client.get('/a')
+    assert r.status == 200
+    yield from r.release()
+
+    r = yield from client.head('/a')
+    assert r.status == 200
+    yield from r.release()
+
+    r = yield from client.get('/b')
+    assert r.status == 200
+    yield from r.release()
+
+    r = yield from client.head('/b')
+    assert r.status == 405
+    yield from r.release()
+
+
+@pytest.mark.parametrize('dft_allow_head,allow_head,status', [
+    (True, False, 405),
+    (True, True, 200),
+    (True, None, 200),
+    (False, False, 405),
+    (False, True, 200),
+    (False, None, 405),
+])
+@asyncio.coroutine
+def test_allow_head(loop, test_client, dft_allow_head, allow_head, status):
+    """
+    Test allow_head on routes.
+    """
+    app = web.Application(loop=loop)
+
+    def handler(_):
+        return web.Response()
+    app.router.set_defaults(allow_head=dft_allow_head)
+    app.router.add_get('/', handler, allow_head=allow_head)
+    client = yield from test_client(app)
+
+    r = yield from client.get('/')
+    assert r.status == 200
+    yield from r.release()
+
+    r = yield from client.head('/')
+    assert r.status == status
+    yield from r.release()